Topographic Seismic Travel-Time Calculation Based on Coarse-Grid Interpolation

Abstract As an important seismic attribute parameter, accurate travel-time computation is essential for simulating seismic wave propagation, locating seismic sources, constructing velocity models, and enabling earthquake early warning systems. In practical scenarios, the influence of complex topography often necessitates the use of nonhorizontal acquisition lines for seismic surveys. Therefore, investigating seismic travel-time computation under undulating terrain is of significant importance. This study systematically investigates travel-time computation methodologies utilizing coarse-grid interpolation techniques in irregular topographic environments and subsequently proposes an enhanced algorithm. Extending prior accuracy, the proposed method adds new grid node types. It adopts a hybrid interpolation strategy, effectively addressing the inefficiency of traditional methods when applied to large-scale models. This enhancement offers a reliable and efficient solution for computing travel times in large-scale, complex velocity models with topographic variations. The effectiveness of the proposed method is validated through error analysis and multiple numerical experiments.